/**
 * Copyright 2007 Jason Horman, Pete Aykroyd
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *    http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.functor;

/**
 * 2 element tuple.
 */
public class Pair<Type1,Type2> extends Tuple {
	public Pair(Type1 o1, Type2 o2) {
		super(o1, o2);
	}

	public Type1 getFirst() {
		return (Type1) get(0);
	}

	public Type2 getSecond() {
		return (Type2) get(1);
	}

	public static <T1,T2> UnaryFunction<Pair<T1,T2>, Pair<T1,T2>> modifyFirst(final UnaryFunction<T1,T1> fn) {
		return new UnaryFunction<Pair<T1,T2>, Pair<T1,T2>>() {
			public Pair<T1, T2> evaluate(Pair<T1, T2> obj) {
				return new Pair(fn.evaluate(obj.getFirst()), obj.getSecond());
			}
		};
	}
}
